1. Field of the Invention
The invention relates primarily to a system for performing an anastomosis between a first hollow tissue structure, for example, a vascular conduit such as a vein, artery or artificial blood vessel, and a second hollow tissue structure, for example, an aorta or another vascular conduit. The invention may, however, find use in other applications.
2. Description of Related Art
Many devices and methods have been proposed for performing an anastomosis (graft) between blood vessels. One of the most common surgical procedures carried out today which requires performing an anastomosis is coronary artery bypass grafting (CABG), commonly referred to as bypass surgery. This procedure is used to treat patients suffering from coronary disease in the form of one or more coronary arteries that are partially or completely blocked by stenoses. When blood flow through the coronary arteries is restricted or occluded, the cardiac muscle tissue becomes deprived of adequate blood flow, which eventually results in death of the muscle tissue. Interventional procedures other than bypass surgery, for example, angioplasty and atherectomy, are also used to treat occluded coronary arteries. However, bypass surgery is usually desirable or necessary to treat patients suffering from severe or multiple coronary artery blockages, or when other interventional procedures have been or would likely be unsuccessful.
In order to bypass a blockage in a coronary artery, the surgeon must anastomose a vascular conduit which is in communication with a source of arterial blood to the coronary artery at a location downstream of the blockage. The vascular conduit may be a native artery carrying blood from the patient's heart, for example, the right or left internal mammary artery (IMA). In such case, the artery may be transected from the patient's body to provide a free end which is prepared for distal anastomosis to the coronary artery. Alternatively, the IMA may be transected and removed from the body and one end prepared for anastomosis to an arterial blood source and the other to a coronary artery. Further, depending on the number of coronary arteries which are blocked, in addition to using the right and/or left IMA, other vascular conduits may be needed. One end of each conduit is prepared for distal anastomosis to the coronary artery, while the other end is prepared for proximal anastomosis to an arterial blood source, for example, the aorta. The vascular conduits may be harvested from the patient's body, suitable examples of which include the left or right IMA, inferior epigastric artery, splenic artery, subclavian artery, saphenous vein, etc. Also, animal or synthetic vascular conduits may be used instead of or in addition to those mentioned above.
The most common form of bypass surgery involves bypassing blockages in multiple coronary arteries, e.g., quadruple, five or six-way bypass procedures. As a result, most bypass procedures require a number of vascular conduits to form the necessary anastomoses. However, there is a limited number of native arterial conduits available which may be used by simply attaching one end to a blocked coronary artery. As such, it is usually necessary to use free conduits or grafts, which requires forming an anastomosis at both ends of each conduit, one end to an arterial blood source and the other end to the blocked coronary artery. The patient's aorta is a desirable arterial blood source to which the proximal end of one or more conduits may be anastomosed. As is the case with all other anastomoses, the surgeon must securely suture the proximal end of each conduit to the patient's aorta in order to obtain a strong, fluid tight connection, which is a highly technical and time consuming procedure. Nevertheless, when performing bypass surgery via conventional, open-chest procedures in which the patient's sternum is split and retracted, the surgeon has essentially unobstructed access to the heart and aorta, which reduces the difficulty of forming the proximal anastomoses between the vascular conduits and the patient's aorta.
During the last several years, however, there has been a movement away from open-chest surgery toward minimally invasive cardiac surgery. Some of the cardiac procedures presently being performed in a minimally invasive manner include, for example, coronary artery bypass, mitral or aortic valve repair or replacement, and septal defect repair. These procedures are typically carried out through incisions made between the ribs, which requires surgeons to operate with considerably less access to the heart and aorta as compared to open-chest procedures. This reduced access to the heart has increased the difficulty and time associated with forming the anastomoses between the vascular conduits and the patient's arteries, and in particular, the proximal anastomoses between the vascular conduits and the patient's aorta. More specifically, the already highly technical procedure of suturing the vascular conduits to the aorta or other arterial blood source (as well as to the coronary arteries) is even more difficult when the surgeon is operating through a small port, e.g., an incision 3 or 4 inches in length. As a secure, fluid tight anastomosis is highly desirable in order to provide long term patency of the conduit bypassing the blockage, minimally invasive cardiac surgery presents significant challenges for the surgeon.
The devices and methods used in conventional open-chest cardiac surgery, however, are not always usable or readily adaptable to carry out minimally invasive cardiac surgery. The use of suture to form the anastomoses in the standard in cardiac surgery. As noted above, though, using suture to anastomose the respective vascular conduits is particularly difficult when performing a minimally invasive cardiac procedure. Although stapling devices are commonly used during laparoscopic procedures to join various tissue structures, they are not designed or easily adaptable for use in minimally invasive cardiac surgery. As a result, there is a need in the art for an effective alternative to using suture in order to carry out minimally invasive cardiac procedures, and in particular forming anastomoses between hollow tissue structures when access to the tissue is limited.